Immunization with Tc52 or its amino terminal domain adjuvanted with c-di-AMP induces Th17+Th1 specific immune responses and confers protection against Trypanosoma cruzi

Abstract

The development of new adjuvants enables fine modulation of the elicited immune responses. Ideally, the use of one or more adjuvants should result in the induction of a protective immune response against the specific pathogen. We have evaluated the immune response and protection against Trypanosoma cruzi infection in mice vaccinated with recombinant Tc52 or its N- and C-terminal domains (NTc52 and CTc52) adjuvanted either with the STING (Stimulator of Interferon Genes) agonist cyclic di-AMP (c-di-AMP), a pegylated derivative of α-galactosylceramide (αGC-PEG), or oligodeoxynucleotides containing unmethylated CpG motifs (ODN-CpG). All groups immunized with the recombinant proteins plus adjuvant: Tc52+c-di-AMP, NTc52+c-di-AMP, CTc52+c-di-AMP, NTc52+c-di-AMP+αGC-PEG, NTc52+CpG, developed significantly higher anti-Tc52 IgG titers than controls. Groups immunized with c-di-AMP and Tc52, NTc52 or CTc52 showed the highest Tc52-specific IgA titers in nasal lavages. All groups immunized with the recombinant proteins plus adjuvant developed a strong specific cellular immune response in splenocytes and lymph node cells with significant differences for groups immunized with c-di-AMP and Tc52, NTc52 or CTc52. These groups also showed high levels of Tc52-specific IL-17 and IFN-γ producing cells, while NTc52+CpG group only showed significant difference with control in IFN-γ producing cells. Groups immunized with c-di-AMP and Tc52, NTc52 or CTc52 developed predominantly a Th17 and Th1immune response, whereas for NTc52+CpG it was a dominant Th1 response. It was previously described that αGC-PEG inhibits Th17 differentiation by activating NKT cells. Thus, in this work we have also included a group immunized with both adjuvants (NTc52+c-di-AMP+αGC-PEG) with the aim to modulate the Th17 response induced by c-di-AMP. This group showed a significant reduction in the number of Tc52-specific IL-17 producing splenocytes, as compared to the group NTc52+c-di-AMP, which has in turn correlated with a reduction in protection against infection. These results suggest that the Th17 immune response developed after immunizing with NTc52+c-di-AMP could have a protective role against T. cruzi infection. Groups NTc52+c-di-AMP, Tc52+c-di-AMP and NTc52PB, were the ones that showed better protection against infection with lower parasitemia and weight loss, and higher survival.

Genetic Engineering of Lactococcus lactis Co-producing Antigen and the Mucosal Adjuvant 3′ 5′- cyclic di Adenosine Monophosphate (c-di-AMP) as a Design Strategy to Develop a Mucosal Vaccine Prototype

“…Very promising results were obtained when c-di-AMP was assessed as adjuvant in different prototypes of mucosal vaccines against different viruses and bacteria ( Sanchez et al, 2014 ; Landi et al, 2017 ; Schulze et al, 2017 ). Particularly, this adjuvant has also been used in previous studies for the design and experimental assessment of subunit vaccines formulations against T. cruzi ( Matos et al, 2017 ; Sanchez Alberti et al, 2017 ). In these studies, recombinant T. cruzi antigens were formulated together with c-di-AMP and were administered nasally, obtaining an immune response that allowed protection after the challenge with the parasite.…”

“…In these studies, recombinant T. cruzi antigens were formulated together with c-di-AMP and were administered nasally, obtaining an immune response that allowed protection after the challenge with the parasite. Moreover, using the Tc52 T. cruzi antigen, Matos and colleagues described a better adjuvant ability of c-di-AMP in comparison with CpG, one of the most potent adjuvants for the development of vaccines against intracellular microorganisms ( Matos et al, 2017 ). Reinforcing these data, our results also show that an engineered L. lactis that overexpresses c-di-AMP and a TS fragment could result in an effective vaccine for Chagas disease.…”

Regulatory Lymphoid and Myeloid Cells Determine the Cardiac Immunopathogenesis of Trypanosoma cruzi Infection

“…In agreement, co-cultures of T. cruzi infected macrophages with live neutrophils isolated from BALB/c and C57BL/6 resulted also in increased and decreased parasite replication, respectively (Luna-Gomes et al, 2014 ), indicating the importance of the mouse genetic background in T. cruzi infection. In addition, anti osteopontin antibody treatment in C57BL/6 infected with the Y strain (Santamaría and Corral, 2013 ) and T. cruzi TC52 antigen immunized C3H/HeN mice infected with the RA strain (Matos et al, 2017 ), induced a high Th1 response that protected mice from infection. However, it is important to point out that the development of severe CCC in humans is also thought to be due to a Th1-specific immune response (Gomes et al, 2003 ), thus some regulation seems to be needed to avoid disease progression.…”

“…Recently, several reports using mice with C57BL/6 background infected with the Tulahuén strain showed that Th17 high levels conferred protection against infection using Il-23 inhibitory BATF2 (Kitada et al, 2017 ), regulatory EBI3 (Böhme et al, 2016 ), IL-17A (Miyazaki et al, 2010 ) and IL-17RA (Tosello Boari et al, 2012 ) deficient mice. On the other hand, immunization of C3H/HeN mice with TC52, a T. cruzi protein with glutathione transferase activity and a vaccine candidate, conferred Th17 specific protection against infection with the RA strain (Matos et al, 2017 ). Similarly, adoptive transfer of BALB/c parasite transialidase (TS) specific Th17 cells into RAG mice (lacking B and T cells) conferred higher protection than TS specific Th1 cells against infection with the Tulahuén strain (Cai et al, 2016 ).…”

Mucosal Heterologous Prime/Boost Vaccination Induces Polyfunctional Systemic Immunity, Improving Protection Against Trypanosoma cruzi

“…However, priming cell-mediated immunity (CMI) through the employment of subunit vaccines models is challenging (19). We have recently reported the efficacy of the STING agonist, 3 ′ 5 ′ -c-di-AMP (CDA) for priming pathogenspecific immune responses where Th1/Th17 balanced immunity proved to be protective against this protozoan parasite (10,20).…”